Last year my iPhone 5 died while on a flight, so I stopped in duty free to buy a new one. I was about to pickup an iphone X when I realized that I couldn't stand it up on it's end and take videos, which I do on a daily basis when practicing my instrument. There was an iphone SE 128GB sitting next to the iphone X for less than 1/2 the price ... I expect to use this phone for another 3 years until they've slowed iOS down enough to make it unusable.

Unexpectedly, the killer feature for me ended up being, "Can I record myself drumming without needing some stupid attachment?"